# 弟

| 弟 | U+5F1F, &#24351; CJK UNIFIED IDEOGRAPH-5F1F |
| ← 弞 [U+5F1E] | CJK Unified Ideographs | 张 → [U+5F20] |

## Translingual
### Han character

弟 (Kangxi radical 57, 弓+4, 7 strokes, cangjie input 金弓中竹 (CNLH), four-corner 8022$_7$, composition ⿹弚丿)

#### Derived characters

* 俤, 㖒, 挮, 涕, 悌, 娣, 綈 (绨), 珶, 梯, 焍, 祶, 睇, 銻 (锑), 稊, 鮷, 豑, 豒, 剃, 鵜 (鹈), 晜, 罤, 鬀, 递

#### References

* Kangxi Dictionary: page 357, character 17
* Dai Kanwa Jiten: character 9737
* Dae Jaweon: page 673, character 19
* Hanyu Da Zidian (first edition): volume 1, page 244, character 10
* Unihan data for U+5F1F

## Chinese
### Glyph origin

Historical forms of the character 弟 :
| Western Zhou | Shuowen Jiezi (compiled in Han) | Liushutong (compiled in Ming) |
| Bronze inscriptions | Small seal script | Transcribed ancient scripts |
| | Old Chinese |
| 梯 | *tʰiːl |
| 睇 | *tʰiːl, *diːls |
| 涕 | *tʰiːlʔ, *tʰiːls |
| 挮 | *tʰiːlʔ |
| 鬀 | *tʰiːls, *diːls |
| 剃 | *tʰiːls |
| 綈 | *diːl |
| 蕛 | *diːl |
| 稊 | *diːl |
| 苐 | *diːl |
| 鵜 | *diːl |
| 銻 | *diːl |
| 鮷 | *diːl |
| 罤 | *diːl |
| 弟 | *diːlʔ, *diːls |
| 娣 | *diːlʔ, *diːls |
| 悌 | *diːlʔ, *diːls |
| 第 | *diːls |
Pictogram (象形) of a spear handle wrapped in a leather strap. The wrapping signified order or sequence, which extended to "younger brother".

### Pronunciation 1

* Mandarin
    (Standard)
       (Pinyin): dì (di$^4$)
       (Zhuyin): ㄉㄧˋ
    (Chengdu, Sichuanese Pinyin): di$^4$
    (Xi'an, Guanzhong Pinyin): dī
* Cantonese
    (Guangzhou–Hong Kong, Jyutping): dai$^6$
    (Dongguan, Jyutping++): doi$^3$
    (Taishan, Wiktionary): ai$^5$ / hai$^4$
* Gan (Wiktionary): ti$^5$
* Hakka
    (Sixian, PFS): thi / thâi
    (Hailu, HRS): ti$^˖$ / tai$^ˋ$
    (Meixian, Guangdong): ti$^4$ / tai$^1$
* Jin (Wiktionary): di$^3$
* Northern Min (KCR): dī
* Eastern Min (BUC): dâ̤ / diê
* Puxian Min (Pouseng Ping'ing): di$^5$ / de$^5$
* Southern Min
    (Hokkien, POJ): tī / tǐ / tē / tě / tî / ti / tih
    (Teochew, Peng'im): di$^6$
* Southern Pinghua (Nanning, Jyutping++): dai$^6$
* Wu (Northern, Wugniu): $^6$di
* Xiang
    (Changsha, Wiktionary): di$^5$ / di$^4$
    (Loudi, Wiktionary): ddi$^5$
* Mandarin
** (Standard Chinese)
*** Hanyu Pinyin: dì
*** Zhuyin: ㄉㄧˋ
*** Tongyong Pinyin: dì
*** Wade–Giles: ti$^4$
*** Yale: dì
*** Gwoyeu Romatzyh: dih
*** Palladius: ди (di)
*** Sinological IPA : /ti⁵¹/
** (Chengdu)
*** Sichuanese Pinyin: di$^4$
*** Scuanxua Ladinxua Xin Wenz: di
*** Sinological IPA : /ti²¹³/
** (Xi'an)
*** Guanzhong Pinyin: dī
*** Sinological IPA : /ti⁵⁵/
* Cantonese
** (Standard Cantonese, Guangzhou–Hong Kong)
*** Jyutping: dai$^6$
*** Yale: daih
*** Cantonese Pinyin: dai$^6$
*** Guangdong Romanization: dei$^6$
*** Sinological IPA : /tɐi̯²²/
** (Dongguan, Guancheng)
*** Jyutping++: doi$^3$
*** Sinological IPA : /tɔi³²/
** (Taishanese, Taicheng)
*** Wiktionary: ai$^5$ / hai$^4$
*** Sinological IPA : /ai³²/, /hai²¹/
* Gan
** (Nanchang)
*** Wiktionary: ti$^5$
*** Sinological IPA : /tʰi¹¹/
* Hakka
** (Sixian, incl. Miaoli and Neipu)
*** Pha̍k-fa-sṳ: thi / thâi
*** Hakka Romanization System: ti / tai$^ˊ$
*** Hagfa Pinyim: ti$^4$ / tai$^1$
*** Sinological IPA: /tʰi⁵⁵/, /tʰai̯²⁴/
** (Hailu, incl. Zhudong)
*** Hakka Romanization System: ti$^˖$ / tai$^ˋ$
*** Sinological IPA: /tʰi³³/, /tʰai⁵³/
** (Meixian)
*** Guangdong: ti$^4$ / tai$^1$
*** Sinological IPA: /tʰi⁵³/, /tʰaɪ⁴⁴/
* Jin
** (Taiyuan)
*** Wiktionary: di$^3$
*** Sinological IPA (old-style): /ti⁴⁵/
* Northern Min
** (Jian'ou)
*** Kienning Colloquial Romanized: dī
*** Sinological IPA : /ti⁵⁵/
* Eastern Min
** (Fuzhou)
*** Bàng-uâ-cê: dâ̤ / diê
*** Sinological IPA : /tɑ²⁴²/, /tiɛ²⁴²/
* Puxian Min
** (Putian, Xianyou)
*** Pouseng Ping'ing: di$^5$
*** Sinological IPA : /ti²¹/
** (Putian, Xianyou)
*** Pouseng Ping'ing: de$^5$
*** Sinological IPA : /te²¹/
* di5 - vernacular;
* de5 - literary.
* Middle Chinese: dejX, dejH
Rime :
| Character | 弟 | 弟 |
| Reading # | 1/2 | 2/2 |
| Initial (聲) | 定 (7) | 定 (7) |
| Final (韻) | 齊 (39) | 齊 (39) |
| Tone (調) | Rising (X) | Departing (H) |
| Openness (開合) | Open | Open |
| Division (等) | IV | IV |
| Fanqie | 徒禮切 | 特計切 |
| Baxter | dejX | dejH |
| Reconstructions |||
| Zhengzhang Shangfang | /dei$^X$/ | /dei$^H$/ |
| Pan Wuyun | /dei$^X$/ | /dei$^H$/ |
| Shao Rongfen | /dɛi$^X$/ | /dɛi$^H$/ |
| Edwin Pulleyblank | /dɛj$^X$/ | /dɛj$^H$/ |
| Li Rong | /dei$^X$/ | /dei$^H$/ |
| Wang Li | /diei$^X$/ | /diei$^H$/ |
| Bernhard Karlgren | /dʱiei$^X$/ | /dʱiei$^H$/ |
| Expected Mandarin Reflex | dì | dì |
| Expected Cantonese Reflex | dai$^6$ | dai$^6$ |
* Old Chinese
    (Baxter–Sagart): /*lˤəjʔ/
    (Zhengzhang): /*diːlʔ/, /*diːls/
Baxter–Sagart system 1.1 (2014) :
| Character | 弟 |
| Reading # | 1/1 |
| Modern Beijing (Pinyin) | dì |
| Middle Chinese | ‹ dej$^X$ › |
| Old Chinese | /*lˁəjʔ/ |
| English | younger brother |
| Notes for Old Chinese notations in the Baxter–Sagart system: * Parentheses "" indicate uncertain presence; * Square brackets "" indicate uncertain identity, e.g. *[t] as coda may in fact be *-t or *-p; * Angle brackets "<>" indicate infix; * Hyphen "-" indicates morpheme boundary; * Period "." indicates syllable boundary. ||
Zhengzhang system (2003) :
| Character | 弟 | 弟 |
| Reading # | 1/2 | 2/2 |
| No. | 2294 | 2297 |
| Phonetic component | 弟 | 弟 |
| Rime group | 脂 | 脂 |
| Rime subdivision | 1 | 1 |
| Corresponding MC rime | 弟 | 第 |
| Old Chinese | /*diːlʔ/ | /*diːls/ |
| Notes | 甲金文象繩束弋（朱芳圃說），繞弋繩須次第不亂方利於射， 爲第初文 | |

#### Definitions

弟
* younger brother
* junior male
* (literary, humble) I; me (between male friends)
* Original form of 第 (dì, “sequence”).

#### Compounds

* 三千弟子
* 上色徒弟
* 上首徒弟
* 不弟
* 世弟
* 介弟
* 仁弟
* 令弟 (lìngdì)
* 佛門弟子 / 佛门弟子
* 佳子弟
* 兄友弟恭 (xiōngyǒudìgōng)
* 兄弟
* 兄弟共妻
* 兄弟會 / 兄弟会 (xiōngdìhuì)
* 兄弟鬩牆 / 兄弟阋墙 (xiōngdìxìqiáng)
* 兄死弟及
* 兄終弟及 / 兄终弟及 (xiōngzhōngdìjí)
* 兄肥弟瘦
* 入室弟子
* 內兄弟 / 内兄弟
* 內弟 / 内弟 (nèidì)
* 八千子弟
* 八旗子弟 (bāqí zǐdì)
* 公昆弟
* 十大弟子
* 博士弟子
* 同胞兄弟 (tóngbāo xiōngdì)
* 呼兄喚弟 / 呼兄唤弟
* 堂兄弟 (tángxiōngdì)
* 堂弟 (tángdì)
* 外弟
* 大弟
* 夫兄弟
* 太弟
* 女弟 (nǚdì)
* 女弟子
* 如兄如弟
* 如兄弟
* 好兄弟 (hǎoxiōngdì)
* 如弟
* 妓弟
* 姻兄弟
* 姻弟
* 婦弟 / 妇弟 (fùdì)
* 嫡傳弟子 / 嫡传弟子
* 嫡親兄弟 / 嫡亲兄弟
* 子弟 (zǐdì)
* 子弟兵 (zǐdìbīng)
* 子弟戲 / 子弟戏
* 子弟書 / 子弟书
* 孝弟 (xiàotì)
* 孝弟力田
* 孿生兄弟 / 孪生兄弟 (luánshēng xiōngdì)
* 宗弟
* 家弟
* 小兄弟
* 小弟 (xiǎodì)
* 巒兄巒弟 / 峦兄峦弟
* 師兄弟 / 师兄弟
* 師弟 / 师弟 (shīdì)
* 帶徒弟 / 带徒弟
* 年弟
* 弟兄 (dìxiong)
* 弟妹 (dìmèi)
* 弟婦 / 弟妇 (dìfù)
* 弟媳 (dìxí)
* 弟媳婦 / 弟媳妇 (dìxífù)
* 弟子 (dìzǐ)
* 弟子員 / 弟子员
* 弟子孩兒 / 弟子孩儿
* 弟弟
* 弟茂德 (Dìmàodé)
* 弟郎
* 徒弟 (túdì)
* 從兄弟 / 从兄弟 (cóngxiōngdì)
* 從弟 / 从弟 (cóngdì)
* 房分兄弟
* 把兄弟 (bǎxiōngdì)
* 拜把兄弟
* 換帖兄弟 / 换帖兄弟
* 故家子弟
* 族兄弟
* 族弟 (zúdì)
* 昆弟
* 昆弟之好
* 梨園子弟 / 梨园子弟 (Líyuán zǐdì)
* 梨園弟子 / 梨园弟子
* 桿弟 / 杆弟
* 母弟 (mǔdì)
* 江東子弟 / 江东子弟
* 清寒子弟
* 淑弟
* 漂蕩子弟 / 漂荡子弟
* 烏衣子弟 / 乌衣子弟
* 生死弟兄 (shēngsǐ dìxiōng)
* 異母兄弟 / 异母兄弟 (yìmǔ xiōngdì)
* 盟兄弟 (méngxiōngdì)
* 硯弟 / 砚弟
* 稱兄道弟 / 称兄道弟 (chēngxiōngdàodì)
* 紈褲子弟 / 纨裤子弟
* 結拜兄弟 / 结拜兄弟 (jiébài xiōngdì)
* 義弟 / 义弟 (yìdì)
* 老兄弟
* 老弟 (lǎodì)
* 胞兄弟 (bāoxiōngdì)
* 胞弟 (bāodì)
* 膏粱子弟
* 至親兄弟 / 至亲兄弟
* 良家子弟
* 苟弟轉酷 / 苟弟转酷
* 萊特兄弟 / 莱特兄弟
* 表兄弟 (biǎoxiōngdì)
* 表弟 (biǎodì)
* 襟弟 (jīndì)
* 誤人子弟 / 误人子弟 (wùrénzǐdì)
* 譜兄弟 / 谱兄弟
* 豈弟 / 岂弟
* 豈弟君子 / 岂弟君子
* 貴族子弟 / 贵族子弟
* 貴遊子弟 / 贵游子弟
* 賢弟 / 贤弟 (xiándì)
* 農家子弟 / 农家子弟
* 遠兄弟 / 远兄弟
* 邸弟
* 酒肉兄弟
* 鋤大弟 / 锄大弟 (chúdàdì)
* 關門弟子 / 关门弟子
* 阿弟 (ādì)
* 難兄難弟 / 难兄难弟
* 露臺弟子 / 露台弟子
* 風月子弟 / 风月子弟
* 香火兄弟
* 高業弟子 / 高业弟子
* 高足弟子

#### Descendants

* → Thai: ตี๋ (dtǐi, “younger brother”) (said by Chinese race)

#### Synonyms

* (younger brother):
| Variety | Location | Words |
| Classical Chinese | Classical Chinese | 弟 |
| Formal (Written Standard Chinese) | Formal (Written Standard Chinese) | 弟弟 |
| Northeastern Mandarin | Beijing | 兄弟, 弟弟 |
| Northeastern Mandarin | Taiwan | 弟弟 |
| Northeastern Mandarin | Harbin | 兄弟, 弟弟 |
| Northeastern Mandarin | Malaysia | 弟弟 |
| Northeastern Mandarin | Singapore | 弟弟 |
| Jilu Mandarin | Jinan | 兄弟, 弟弟 |
| Jiaoliao Mandarin | Yantai (Muping) | 兄兒, 兄弟 |
| Central Plains Mandarin | Luoyang | 兄弟 |
| Central Plains Mandarin | Wanrong | 兄弟 male speaker, 弟子 female speaker |
| Central Plains Mandarin | Xi'an | 兄弟 |
| Central Plains Mandarin | Xining | 兄弟, 弟弟 |
| Central Plains Mandarin | Xuzhou | 弟弟, 兄弟 |
| Central Plains Mandarin | Sokuluk (Gansu Dungan) | 兄弟 |
| Lanyin Mandarin | Yinchuan | 兄弟 |
| Lanyin Mandarin | Ürümqi | 弟弟, 兄弟, 富康子 |
| Southwestern Mandarin | Chengdu | 弟娃兒, 兄弟, 弟弟 |
| Southwestern Mandarin | Wuhan | 弟弟, 兄弟 |
| Southwestern Mandarin | Guiyang | 弟, 兄弟, 弟弟 childish |
| Southwestern Mandarin | Liuzhou | 弟, 阿弟, 老弟 |
| Jianghuai Mandarin | Nanjing | 弟弟, 兄弟 |
| Jianghuai Mandarin | Yangzhou | 兄弟, 弟弟 |
| Jianghuai Mandarin | Nantong | 弟子 |
| Jianghuai Mandarin | Hefei | 兄弟, 弟弟 |
| Cantonese | Guangzhou | 細佬, 弟弟 |
| Cantonese | Hong Kong | 細佬, 弟弟 |
| Cantonese | Hong Kong (San Tin; Weitou) | 細佬 |
| Cantonese | Hong Kong (Kam Tin; Weitou) | 細佬 |
| Cantonese | Hong Kong (Ting Kok) | 細佬 |
| Cantonese | Hong Kong (Tung Ping Chau) | 阿弟 |
| Cantonese | Macau | 細佬 |
| Cantonese | Guangzhou (Panyu) | 細佬 |
| Cantonese | Guangzhou (Huashan, Huadu) | 細佬 |
| Cantonese | Guangzhou (Conghua) | 細佬 |
| Cantonese | Guangzhou (Zengcheng) | 細佬 |
| Cantonese | Foshan | 細佬 |
| Cantonese | Foshan (Shatou, Nanhai) | 細佬 |
| Cantonese | Foshan (Shunde) | 細佬 |
| Cantonese | Foshan (Sanshui) | 細佬 |
| Cantonese | Foshan (Mingcheng, Gaoming) | 細佬 |
| Cantonese | Zhongshan (Shiqi) | 細佬 |
| Cantonese | Zhuhai (Qianshan, Xiangzhou) | 細佬 |
| Cantonese | Zhuhai (Shangheng, Doumen; Tanka) | 細佬 |
| Cantonese | Zhuhai (Doumen) | 細佬 |
| Cantonese | Jiangmen (Baisha) | 細佬 |
| Cantonese | Jiangmen (Xinhui) | 細佬 |
| Cantonese | Taishan | 細佬, 阿弟, 細, 弟 |
| Cantonese | Kaiping (Chikan) | 阿弟, 細佬 |
| Cantonese | Enping (Niujiang) | 阿弟 |
| Cantonese | Heshan (Yayao) | 細佬 |
| Cantonese | Dongguan | 細佬, 弟弟 |
| Cantonese | Shenzhen (Shajing, Bao'an) | 細佬 |
| Cantonese | Shaoguan | 細佬 |
| Cantonese | Yangjiang | 小弟 |
| Cantonese | Kuala Lumpur (Guangfu) | 細佬 |
| Cantonese | Singapore (Guangfu) | 細佬 |
| Gan | Nanchang | 老弟, 兄弟 |
| Gan | Lichuan | 弟 |
| Gan | Pingxiang | 老弟 |
| Hakka | Meixian | 老弟, 老弟仔 |
| Hakka | Xingning | 老弟, 老弟里 |
| Hakka | Huizhou (Huicheng; Bendihua) | 老弟 |
| Hakka | Huiyang | 老弟 |
| Hakka | Huidong (Daling) | 老弟 |
| Hakka | Dongguan (Qingxi) | 老弟 |
| Hakka | Shenzhen (Shatoujiao) | 老弟 |
| Hakka | Zhongshan (Nanlang Heshui) | 老弟 |
| Hakka | Wuhua (Shuizhai) | 老弟 |
| Hakka | Wuhua (Huacheng) | 老弟 |
| Hakka | Wuhua (Changbu) | 老弟 |
| Hakka | Wuhua (Mianyang) | 老弟 |
| Hakka | Wuhua (Meilin) | 老弟 |
| Hakka | Heyuan (Bendihua) | 老弟 |
| Hakka | Wengyuan | 老弟 |
| Hakka | Shaoguan (Qujiang) | 老弟 |
| Hakka | Lianshan (Xiaosanjiang) | 老弟 |
| Hakka | Liannan | 老弟 |
| Hakka | Guangzhou (Lütian, Conghua) | 弟弟 |
| Hakka | Jiexi | 老弟 |
| Hakka | Luhe | 老弟 |
| Hakka | Zhao'an (Xiuzhuan) | 阿弟 |
| Hakka | Changting | 老弟 |
| Hakka | Wuping | 老弟 |
| Hakka | Wuping (Yanqian) | 老弟子 |
| Hakka | Wuping (Pingyu) | 老弟子 |
| Hakka | Liancheng | 老弟 |
| Hakka | Ninghua | 老弟 |
| Hakka | Yudu | 老弟 |
| Hakka | Ningdu | 老弟 |
| Hakka | Ruijin | 老弟 |
| Hakka | Shicheng | 老弟 |
| Hakka | Shangyou (Shexi) | 老弟 |
| Hakka | Tonggu (Sandu) | 老弟 |
| Hakka | Ganzhou (Panlong) | 老弟 |
| Hakka | Dayu | 弟佬 |
| Hakka | Miaoli (N. Sixian) | 老弟 |
| Hakka | Pingtung (Neipu; S. Sixian) | 老弟 |
| Hakka | Hsinchu County (Zhudong; Hailu) | 老弟 |
| Hakka | Taichung (Dongshi; Dabu) | 老弟 |
| Hakka | Hsinchu County (Qionglin; Raoping) | 老弟 |
| Hakka | Yunlin (Lunbei; Zhao'an) | 阿弟 |
| Hakka | Hong Kong | 老弟 |
| Hakka | Yangxi (Tangkou) | 老弟 |
| Hakka | Yangchun (Sanjia) | 細佬 |
| Hakka | Xinyi (Sihe) | 老弟, 細佬 |
| Hakka | Xinyi (Qianpai) | 老弟, 細佬 |
| Hakka | Gaozhou (Xindong) | 老弟 |
| Hakka | Maoming (Shalang, Dianbai) | 老弟 |
| Hakka | Huazhou (Xin'an) | 老弟 |
| Hakka | Lianjiang (Shijiao) | 老弟 |
| Hakka | Lianjiang (Qingping) | 阿弟, 老弟 |
| Hakka | Mengshan (Xihe) | 老弟 |
| Hakka | Luchuan | 老弟 |
| Hakka | Sabah (Bao'an) | 老弟 |
| Hakka | Sabah (Longchuan) | 老弟 |
| Hakka | Senai (Huiyang) | 老弟 |
| Hakka | Sungai Tapang, Batu Kawa (Hepo) | 老弟 |
| Hakka | Singkawang | 阿弟, 老弟 |
| Huizhou | Jixi | 弟 |
| Jin | Taiyuan | 兄弟, 弟弟 |
| Jin | Xinzhou | 兄弟 |
| Northern Min | Jian'ou | 弟仔 |
| Eastern Min | Fuzhou | 依弟 face-to-face, 弟 |
| Southern Min | Xiamen | 小弟, 阿弟 face-to-face |
| Southern Min | Quanzhou | 小弟, 阿弟 face-to-face |
| Southern Min | Zhangzhou | 小弟, 阿弟 face-to-face |
| Southern Min | Zhao'an | 細弟仔, 細弟 |
| Southern Min | Kaohsiung | 小弟 |
| Southern Min | Yilan | 小弟 |
| Southern Min | Changhua (Lukang) | 小弟 |
| Southern Min | Taichung | 小弟 |
| Southern Min | Taichung (Wuqi) | 小弟 |
| Southern Min | Tainan | 小弟 |
| Southern Min | Taitung | 小弟 |
| Southern Min | Hsinchu | 小弟 |
| Southern Min | Penghu (Magong) | 小弟 |
| Southern Min | Penang (Hokkien) | 小弟, 阿棣 |
| Southern Min | Singapore (Hokkien) | 小弟, 阿弟 face-to-face |
| Southern Min | Manila (Hokkien) | 小弟 |
| Southern Min | Chaozhou | 阿弟 |
| Southern Min | Shantou | 阿弟 |
| Southern Min | Jieyang | 阿弟 |
| Southern Min | Haifeng | 阿弟, 弟, 弟弟 |
| Southern Min | Bangkok (Teochew) | 阿弟 |
| Southern Min | Johor Bahru (Teochew) | 阿弟 |
| Southern Min | Singapore (Teochew) | 阿弟 |
| Southern Min | Leizhou | 老弟 |
| Southern Min | Haikou | 老弟 non-face-to-face, 阿弟 face-to-face |
| Zhongshan Min | Zhongshan (Longdu, Shaxi) | 細佬, 弟弟 |
| Zhongshan Min | Zhongshan (Sanxiang) | 細佬 |
| Southern Pinghua | Nanning (Tingzi) | 老弟 |
| Wu | Shanghai | 弟弟, 阿弟, 兄弟 |
| Wu | Shanghai (Chongming) | 兄弟 |
| Wu | Suzhou | 兄弟, 弟弟 |
| Wu | Danyang | 弟子 |
| Wu | Hangzhou | 阿弟, 弟弟 |
| Wu | Ningbo | 阿弟, 弟弟 face-to-face |
| Wu | Wenzhou | 阿弟 |
| Wu | Jinhua | 弟 |
| Xiang | Changsha | 老弟, 弟弟 |
| Xiang | Loudi | 老弟 |
| Xiang | Shuangfeng | 老弟, 弟弟 |
| Xiang | Hengyang | 老弟 |

### Pronunciation 2

* For pronunciation and definitions of 弟 – see 悌 (“to love and respect one's elder brothers; peaceful; at ease”). (This character is an ancient form of 悌).

### References

* “Entry #3144”, in 教育部臺灣台語常用詞辭典 [Dictionary of Frequently-Used Taiwanese Taigi] (overall work in Mandarin and Hokkien), Ministry of Education, R.O.C., 2025.
* “弟”, in 漢語多功能字庫 (Multi-function Chinese Character Database)‎, 香港中文大學 (the Chinese University of Hong Kong), 2014–

## Japanese
### Kanji

(Second grade kyōiku kanji)

#### Readings

* Go-on: だい (dai, Jōyō $^†$)
* Kan-on: てい (tei, Jōyō)
* Kan’yō-on: で (de, Jōyō $^†$)
* Kun: おと (oto, 弟)、おとうと (otōto, 弟, Jōyō)

### Etymology 1

* Kanji in this term
* 弟
* おと Grade: 2
* kun'yomi
For pronunciation and definitions of 弟 – see the following entry. :
| 【乙おと】S | [noun] [from 712] (archaic) a younger sibling [noun] [from late 1500s] (archaic) the youngest sibling [noun] [from late 1500s] (archaic) clipping of 乙娘 (oto musume) a young woman [noun] [from late 1500s] (archaic, Noh theater) clipping of 乙御前 (oto goze): a stock character in 狂言 (kyōgen) comic interludes, played as a plump and clumsy but earnest young woman [prefix] applied to a noun denoting a person, or to a person's name: [prefix] next, younger, youngest [prefix] beautiful, beloved, cute, dear |
(This term, 弟, is an alternative spelling of the above term.) :

### Etymology 2

* Kanji in this term
* 弟
* おとうと Grade: 2
* kun'yomi
/otopito/ → /otoɸito/ → /otowito/ → /*otowuto/ → /otouto/ → /otoːto/
Originally a compound of 弟 (oto, “younger sibling”) +‎ 人 (hito, “person”).

#### Pronunciation

* (Tokyo) おとーと [òtóótóꜜ] (Odaka – [4])
* IPA: [o̞to̞ːto̞]

#### Noun

弟(おとうと) • (otōto)
* one’s own younger brother
* a younger male
(alternative reading hiragana おとっ, rōmaji oto')
* (Kagoshima) younger brother

##### Usage notes

Used when referring to one’s own younger brother. To refer to someone else’s younger brother, the suffixed form 弟さん (otōto-san) is used instead. When addressing one’s own younger brother, the given name is used, often with a suffix, such as 太郎君 (Tarō-kun). Contrast with addressing one’s own older brother, when one uses the honorific お兄さん (onīsan).

### References

* ↑ Shōgaku Tosho (1988) 国語大辞典（新装版） [Unabridged Dictionary of Japanese (Revised Edition)] (in Japanese), Tōkyō: Shogakukan, →ISBN
* 1 2 Matsumura, Akira, editor (2006), 大辞林 [Daijirin] (in Japanese), Third edition, Tokyo: Sanseidō, →ISBN
* ↑ NHK Broadcasting Culture Research Institute, editor (1998), NHK日本語発音アクセント辞典 [NHK Japanese Pronunciation Accent Dictionary] (in Japanese), Tokyo: NHK Publishing, Inc., →ISBN

## Korean
### Etymology

From Middle Chinese 弟 (MC dejX).
* Recorded as Middle Korean 똉〯 (Yale: ttyěy$^?$) in Dongguk Jeongun (東國正韻 / 동국정운), 1448.
* Recorded as Middle Korean 뎨〯 (tyěy)$^訓$ (Yale: tyěy) in Hunmong Jahoe (訓蒙字會 / 훈몽자회), 1527.
* Recorded as Middle Korean 뎨 ( tyey)$^訓$ (Yale: tyey) in Gwangju Cheonjamun (光州千字文 / 광주천자문), 1575.
* Recorded as Middle Korean 뎨 ( tyey)$^訓$ (Yale: tyey) in Sinjeung Yuhap (新增類合 / 신증유합), 1576.

### Pronunciation

* (SK Standard/Seoul) IPA: [t͡ɕe̞(ː)]
* Phonetic hangul: [제(ː)]
** Though still prescribed in Standard Korean, most speakers in both Koreas no longer distinguish vowel length.

### Hanja

Wikisource 弟 (eumhun 아우 제 (au je))
* hanja form of 제 (“younger brother”)

#### Compounds

* 도제 (徒弟, doje)
* 매제 (妹弟, maeje)
* 사제 (師弟, saje)
* 의형제 (義兄弟, uihyeongje)
* 자제 (子弟, jaje)
* 제수 (弟嫂, jesu)
* 제자 (弟子, jeja)
* 처제 (妻弟, cheoje)
* 형제 (兄弟, hyeongje)

### References

* 국제퇴계학회 대구경북지부 (國際退溪學會 大邱慶北支部) (2007). Digital Hanja Dictionary, 전자사전／電子字典.

## Vietnamese
### Han character

弟: Hán Nôm readings: đệ, dễ
* This term needs a translation to English. Please help out and add a translation, then remove the text {{rfdef}}.